Energy Sources in Urology

-Dr. Shubham Lavania

30/06/2017

“HEAT CURES WHEN EVERYTHING ELSE FAILS”- Hippocrates

Tissue Dissection and CauterizationIntracorporeal LithotriptersESWL

• Electrosurgery ??Classification -Type of Generator Used:A. Simple generator: mono/ Bipolar cauteryB. Advanced Bipolar System:

I. LigasureII. PK systemIII. Enseal

C. UltrasonicD. Integrated US & ABSE. Argon Beam coagulatorF. LasersG. Others: radiofrequency, microwave, Cryo

Mono polar: •Circuit•100 W of power to the tissue at voltages ranging from 100 to 5000 volts•Cut, Coagulate, blend•Fulgration , dessiccation

Bipolar:Circuit

Safety: 1. Patient pad placement2. Demodulated current (250-2000KHz)3. Direct application4. Direct coupling5. Insulation failure6. Capacitative coupling

Ligasure:-

• Combines pressure and energy

• Uses higer current & low voltage

• Vs upto 7mm

Gyrus PK tissue management sysytem:-

• Vapour pulse coagulation

Enseal:-

• Patented blade & smart electrode technology

Physics of US:

2types: Low power: CUSA

High power(55.5 kHz): Harmonic– Working

– Advantage

Integrated US and ABG: Thunderbeat

Argon beam Coagulation: uses radiofrequency electrical energy.

• Properties of Argon

• Non contact, monopolar electrothermalhemostases.

• Use/ drawback

Radiofrequency ablation: probe+ radiofrequency generator= >100⁰C

Use in tumor ablation

Microwave ablation: ultra high speed (2450MHz) alternating field current.

Cryotherapy: rapid cooling of cell and thawing.

Limited uses

Lasers• “light amplification by stimulated emission of

electromagnetic radiation.”

• Each wave exists as a bundle of energy

• Properties :– Monochromatic

– Coherent

– Directionality

• Pulsed or continous

• The power of the laser is equal to the energy over time

• Light-Tissue Interaction-

Types of LasersNeodymium:Yttrium-Aluminum-Garnet:

– wavelength of 1064 nm

– Penetration- 1 cm

Potassium Titanyl Phosphate– wavelength to 532 nm

Holmium:YAG– 2140-nm pulsed laser

– Ts pene-0.5mm

Thulium:YAG– 2000 nm

– Diode laser

Intracorporeal Lithotripters

Extracorporeal Shock wave Lithotripsy

Physical Principles

• Shock wave focusing-sufficient strength only at the target (F2)

• Generator type:

1. Electro hydrolic

2. Electro megnetic

3. peizoelectric

Imaging Systems

1. Fluoroscopy

2. Ultrasound

3. Combined

Anesthesia

• discomfort experienced~energy density & size of F2

• Narcotic, sedative-hypnotics

• EMLA cream

•shock wave profile•Mechanics of stone fragmentation1. Spall fracture2. Squeezing-splitting or

circumferential compression3. Shear stress4. Superfocusing5. Cavitation6. Dynamic fracture process

Bioeffects: Clinical Studies• Acute extra renal damage: Liver, spleen pancreas,

cardiac, muscles.• Acute Renal Injury: hematuria, subcapsular

hematoma• Chronic Renal Injury: systemic blood pressure,

↓renal function, ↑ rate of stone recurrence, and the induction of brushite stone disease

Risk Factors for Shock Wave Lithotripsy• Age Obesity• Coagulopathies Thrombocytopenia• Diabetes mellitus Coronary heart disease• Preexisting hypertension

Aggravating Factors• Number of shocks• Period of shock wave administration: Shorter period

increases damage• Accelerating voltage: Higher voltage increases damage• Type of shock wave generator: First- versus

second/third-generation devices• Kidney size: Juvenile versus adult• Preexisting renal impairmentMitigating Factors• Pretreatment with 100 to 500 shocks at low energy

level to reduce lesion size• Treatment at a slow rate of shock wave delivery (≤60

shocks/min)

AUA Recommendations• Clinicians should inform patients that SWL is the

procedure with the least morbidity and lowest complication rate. S R; Grade B

• Routine stenting should not be performed in patients undergoing SWL. S R;Grade B

• In symptomatic patients with a total non-lower pole renal stone burden ≤ 20 mm, clinicians may offer SWL or URS. SR grade B

• Clinicians should offer SWL or URS to patients with symptomatic ≤ 10 mm lower pole renal stones

• In pediatric patients with a total renal stone burden ≤20mm, clinicians may offer SWL or URS as first-line therapy. MR; Grade C